Turbine for a dental handpiece

ABSTRACT

A turbine for a dental handpiece. The turbine (10) includes a rotor housing (16) fabricated of a ceramic material, the rotor housing defining a cylindrical rotor chamber (18) therein. An inlet port (20) is provided in the rotor housing (16) for placing the rotor chamber in fluid communication with a source of pressurized fluid, and an outlet port (22) is provided for exhausting the pressurized fluid from the rotor chamber (18). The turbine (10) also includes a rotor member (24) mounted in the rotor chamber (18) of the rotor housing, the rotor member also being fabricated of a ceramic material. The rotor member (24) defines a first end portion (28) which is received through an opening (38) provided in the rotor housing (16) for engaging and supporting a dental tool member (14). The rotor member (24) also includes a rotor disk (32) which carries a plurality of blades (34), and which is selectively rotated by the flow of pressurized fluid within the rotor chamber (18).

TECHNICAL FIELD

This invention relates to a turbine for a dental handpiece. In thisparticular invention the turbine includes a rotor housing fabricated ofa ceramic material and a rotor member rotatably mounted therein which isalso fabricated of a ceramic material.

BACKGROUND ART

Dental handpieces which incorporate pneumatic or electric turbines forselectively rotating cutting and polishing tools have been in use formany years. For example, such handpieces are disclosed in U.S. Pat. Nos.4,983,121; 4,941,828; and 4,921,424. However, in recent years concernhas arisen over the possible transmission of disease through the use ofnon-sterile handpieces. Whereas wiping a handpiece with a disinfectantwas once considered sufficient to obviate disease transmission, it isnow considered an inadequate procedure, and autoclaving or chemiclavingof handpieces between patients is now recommended. However, repeatedautoclaving or chemiclaving tends to damage the turbines of conventionalhandpieces and shorten their useful life. In this regard, modernsterilization techniques can cause rusting metal components, changes inmetal tolerances, bearing cage fractures, lubricant degradation, andgasket and o-ring degradation.

Efforts have been made to design handpieces turbines which betterwithstand sterilization. For example, in some cases the turbines of thehandpiece have been provided with ceramic ball bearings to increasebearing life and obviate the need for the use of a lubricant. Further,in some cases heat resistant O-rings are being used. For example, the430 SWL handpiece manufactured by Star Dental, a division of Den-Tal-Ez,Inc. of Lancaster, Pa., incorporates such features. However, suchfeatures offer only a partial solution to the problem.

Therefore, it is an object of the present invention to provide a turbinefor a dental handpiece which can withstand repeated autoclaving orchemiclaving.

It is another object of the present invention to provide a dentalhandpiece which does not require the use of ball bearings or lubricants.

Yet another object of the present invention is to provide a dentalhandpiece which is lightweight, yet durable.

Still another object of the present invention is to provide a dentalhandpiece which is inexpensive to manufacture and maintain.

DISCLOSURE OF THE INVENTION

Other objects and advantages will be accomplished by the presentinvention which provides a turbine for a dental handpiece. The turbineincludes a rotor housing fabricated of a ceramic material, the rotorhousing defining a cylindrical rotor chamber therein. An inlet port isprovided in the rotor housing for placing the rotor chamber in fluidcommunication with a source of pressurized air or other fluid, and anoutlet port is provided for exhausting the pressurized air or fluid fromthe rotor chamber. The turbine also includes a rotor member rotatablymounted in the rotor chamber of the rotor housing, the rotor member alsobeing fabricated of a ceramic material. The rotor member includes ashaft portion which defines a first end portion which is receivedthrough a rotor shaft opening provided in the rotor housing. The firstend portion of the shaft portion of the rotor member serves to engageand rotatably support a cutting or polishing tool. The rotor member alsoincludes a rotor disk which carries a plurality of blade members, therotor disk being rotatably positioned within the rotor chamber betweenthe inlet port and the outlet port so as to be selectively rotated bythe flow of pressurized fluid between the inlet and outlet ports of therotor housing.

BRIEF DESCRIPTION OF THE DRAWINGS

The above mentioned features of the invention will be more clearlyunderstood from the following detailed description of the invention readtogether with the drawings in which:

FIG. 1 illustrates a perspective view, partially in section, of aturbine of the present invention.

FIG. 2 illustrates a side elevation view, in section, of a turbine ofthe present invention.

FIG. 3 illustrates a diagrammatic side elevation view of the blades ofthe rotor member of a turbine of the present invention.

FIG. 4 illustrates a side elevation view of a dental handpieceincorporating a turbine of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

A turbine for a dental handpiece incorporating various feature of thepresent invention is illustrated generally at 10 in the Figures. Asillustrated in FIG. 4, the turbine 10 is designed to be supported on ahandle 12, the turbine 10 and the handle 12 comprising a dentalhandpiece. The turbine 10 is designed to selectively rotate various toolmembers used in dental procedures, such as, for example, the illustratedtool member 14. As will be discussed in detail below the turbine 10 isdriven by air, or other fluid, under pressure supplied by a suitablesource of pressurized fluid (not shown), such as a compressor.

The turbine 10 includes a rotor housing 16 fabricated of a ceramicmaterial. In one preferred embodiment the ceramic material is a highdensity aluminum oxide ceramic, such as SP 9.9 manufactured by Speceram.However, there are other high density ceramic materials which may besuitable, and the high density aluminum oxide ceramic referenced hereinis merely illustrative of one suitable ceramic fabricating material. Thehousing 16 is typically cylindrical in shape and defines a cylindricalrotor chamber 18. An inlet port 20 is provided in the housing 16 forplacing the rotor chamber 18 in fluid communication with the source ofpressurized fluid, and an outlet port 22 is provided for exhaustingfluid from the chamber 18. As illustrated in FIG. 4, the inlet port 20can be connected to a suitable source of pressurized fluid with a supplyconduit 17 which extends through the handle 12, and, similarly, anexhaust conduit 19, which communicates with the outlet port 22 andextends through the handle 12, can be provided in order to facilitatethe exhausting of fluid from the handpiece.

As best illustrated in FIGS. 1 and 2, a rotor member 24 is rotatablymounted in the rotor chamber 18 of the housing 16. The rotor member 24is also fabricated of a ceramic material, which in the preferredembodiment is a high density aluminum oxide ceramic as discussed above.The rotor member 24 includes a shaft portion 26 defining first andsecond end portions 28 and 30, respectively, and a rotor disk 32provided with a plurality of radially disposed blades 34.

With respect to the rotational support of the rotor member 24 within thehousing 16, in the preferred illustrated embodiment the rotor housing 16defines a first end portion 36 which is provided with an opening 38through which the first end portion 28 of the shaft portion 26 isreceived such that the outboard end of the first end portion 28 isexterior to the housing 16. The rotor housing 16 also defines a secondend portion 40 which is provided with a further opening 42, and therotor housing 16 includes a removable cap member 44 which is received insuch further opening 42 so as to define the rear wall of the housing 16.The cap member 44 is also fabricated of a ceramic material, which in thepreferred embodiment is a high density aluminum oxide ceramic asdiscussed above.

The cap member 44 is provided with an annular receptor 46 whichrotatably receives the second end portion 30 of the shaft portion 26 ofthe rotor member 24. The receptor 46 defines an end wall 48 which isprovided with a centrally disposed indentation 50 receptive of thesecond end portion 30 of the shaft portion 26. In this regard, thesecond end portion 30 of the shaft portion 26 has a conical end 52, atleast the outboard portion of which is rotatably received in theindentation 50 of the receptor 46 to facilitate supporting the rotormember 24 in the desired coaxial position within the rotor chamber 18.

The fabrication of the rotor housing 16, the cap member 44 and the rotormember 24 from high density ceramics provides the turbine 10 with greatadvantages over the prior art turbines which utilize conventional metalfabricating materials. In this regard, aluminum oxide ceramics are lightweight, yet have high friction, abrasion and compression strengths, andare corrosion and heat-resistant. Thus, the use of a ceramic fabricatingmaterial provides greater durability and less susceptibility to ware.Also, with such high density ceramic materials there is less expansionand contraction of the material due to changes in temperature than isthe case with conventional metal fabricating materials, and beingconstructed of a high density ceramic material, the components of theturbine 10 are less susceptible to damage as a result of repetitiveautoclaving and/or chemiclaving.

With respect to the operation of the turbine 10, it will be noted thatwhen the rotor member 24 is rotatably journalled in the opening 38 andthe receptor 46, with the outboard portion of the conical end 52 in theindentation 50, the rotor disk 32 is disposed in the chamber 18 betweenthe inlet port 20 and the outlet port 22 so as to utilize the kineticenergy of the flow of fluid through the chamber 18. In this regard, theblades 34 are selectively pitched such that the flow of fluid throughthe chamber 18 produces rotation of the rotor member 24 in the directionof the arrow 55. Of course, such rotation of the rotor member 24 resultsin the desired rotation of the tool member 14 mounted in the first endportion 28 of the rotor member 24.

More specifically, and as best illustrated in FIG. 3, in the preferredembodiment each blade 34 defines a trailing face 54 which is oriented atapproximately a ten degree (10°) angle relative to the rotational axisof rotor member 24 and the airflow in the chamber 18. Also, each blade34 defines a leading face 56 which is oriented at a selected greaterangle relative to the rotational axis of rotor member 24 than the angleof the trailing face 54, such that the space between the blades 34widens toward the low pressure surface 58 of the rotor member 24 tofacilitate efficient fluid flow through the rotor member 24. Of course,the illustrated rotor blade configuration simply constitutes onepreferred configuration and other blade configurations may be used toproduce the desire rotation.

It will be recognized by those skilled in the art that the use of a highdensity ceramic fabricating material for the housing 16, the rotormember 24 and the cap member 44 obviates the need for mechanicalbearings between the rotor member 24 and the housing 16 or between therotor member 24 and cap member 44. As noted above, the ceramic materialis light weight and ware resistant. However, in order to facilitate thefree rotation of the rotor member 24 in the rotor housing 16, in thepreferred embodiment the first end portion 28 of the shaft portion 26defines a polished bearing surface portion 60 (see FIG. 2) proximate thepoint where the first end portion 28 is received through the opening 38.Similarly, a further polished bearing surface portion 62 is provided onthe second end portion 30 of the shaft portion 26 proximate the pointwhere the second end portion 30 is received in the annular receptor 46of the cap member 44.

Further, it will be noted that the inlet port 20 and the outlet port 22are disposed such that fluid flow through the rotor chamber 18 in theproximity of the rotor disk 32 is in the direction of the cap member 44or rear wall of the housing 16. As a result, the fluid flow biases therotor member 24 in the direction of the cap member 44 such that duringoperation the outboard portion of the conical end 52 of the rotor memberremains seated in the indentation 50 so as to maintaining the desirecoaxial position of the rotor member 24 within the rotor chamber 18. Asa result friction between the rotor member 24 and the housing 16 and capmember 44 is minimized.

In light of the above it will be recognized that the present inventionprovides a turbine for a dental handpiece having great advantages overthe prior art. Since the various components of the turbine 10 arefabricated of a high density ceramic, the turbine is light weight, yetdurable and can withstand repeated autoclaving and chemiclaving. Theconstruction of the turbine 10 obviates the need for ball bearings whichare susceptible to damage from repeated autoclaving or chemiclaving, andobviates the need for lubricants which tend to degrade as a result ofrepeated sterilizations. However, while a preferred embodiment has beenshown and described, it will be understood that there is no intent tolimit the invention to such disclosure, but rather it is intended tocover all modifications and alternate constructions falling within thespirit and scope of the invention as defined in the appended claims.

I claim:
 1. A turbine for a dental handpiece for selectively rotating atool member, said turbine comprising:a rotor housing fabricated of aceramic material, said rotor housing defining a rotor chamber and beingprovided with an inlet port for placing said rotor chamber in fluidcommunication with a source of pressurized fluid whereby pressurizedfluid is selectively supplied to said rotor chamber, and with an outletport for exhausting said pressurized fluid from said rotor chamber, saidrotor housing being provided with a rotor shaft opening communicatingwith said rotor chamber; and a rotor member rotatably mounted in saidrotor chamber of said rotor housing, said rotor member being fabricatedof a ceramic material, said rotor member including a shaft portiondefining a first end portion received through said rotor shaft openingof said rotor housing for engaging and supporting said tool member, saidrotor member also including a rotor disk carrying a plurality of blademembers, said rotor disk being rotatably positioned within said rotorchamber so as to be selectively rotated by the flow of said pressurizedfluid between said inlet port and said outlet port of said rotorhousing.
 2. The turbine of claim 1 wherein said ceramic material ofwhich said rotor housing and said rotor member are fabricated comprisesan aluminum oxide ceramic.
 3. The turbine of claim 1 wherein said rotorchamber is cylindrical and said rotor shaft opening is coaxiallydisposed at a first end of said rotor housing, said rotor housing beingprovided with a further opening at a second end of said housingcommunicating with said rotor chamber, and wherein said rotor housingincludes a cap member for being received in said further opening of saidrotor housing, said cap member being fabricated of a ceramic material.4. The turbine of claim 3 wherein said cap member is provided with anannular receptor having an end wall defining a coaxial indentation, andwherein said rotor member defines a second end portion having a conicaloutboard end, at least a portion of which is rotatably received in saidindentation of said annular receptor of said cap member.
 5. The turbineof claim 4 wherein said ceramic material of which said rotor housing,said rotor member and said cap member are fabricated comprises analuminum oxide ceramic material.
 6. The turbine of claim 1 wherein saidrotor chamber is cylindrical and said rotor shaft opening is coaxiallydisposed at a first end of said rotor housing, said rotor chamberdefining a rear wall provided with an annular receptor having an endwall defining an indentation, and wherein said rotor member defines asecond end portion having a conical outboard end, at least a portion ofwhich is rotatably received in said indentation of said annularreceptor.
 7. The turbine of claim 6 wherein said ceramic material ofwhich said rotor housing and said rotor member are fabricated comprisesan aluminum oxide ceramic.
 8. A turbine for a dental handpiece forselectively rotating a tool member, said turbine comprising:a rotorhousing fabricated of an aluminum oxide ceramic material, said rotorhousing defining a cylindrical rotor chamber and being provided with aninlet port for placing said rotor chamber in fluid communication with asource of pressurized fluid whereby pressurized fluid is selectivelysupplied to said rotor chamber, and with an outlet port for exhaustingsaid pressurized fluid from said rotor chamber, said rotor housing beingprovided with a rotor shaft opening at a first end of said rotor housingcommunicating with said rotor chamber and a further opening at a secondend of said housing communicating with said rotor chamber; a cap memberfor being received in said further opening of said rotor housing, saidcap member being fabricated of an aluminum oxide ceramic, said capmember defining an annular receptor defining an end wall provided with acoaxial indentation; and a rotor member rotatably mounted in said rotorchamber of said rotor housing, said rotor member being fabricated of analuminum oxide ceramic material, said rotor member including a shaftportion defining a first end portion received through said rotor shaftopening of said rotor housing for engaging and supporting the toolmember, and defining a second end portion having a conical outboard end,at least a portion of which is rotatably received in said indentation ofsaid annular receptor of said cap member, said rotor member alsoincluding a rotor disk carrying a plurality of blade members, said rotordisk being rotatably positioned within said rotor chamber between saidinlet port and said outlet port so as to be selectively rotated by theflow of said pressurized fluid between said inlet port and said outletport of said rotor housing.